This tool can be used to check for and remove orphaned BLOB
column parts from NDB tables, as
well as to generate a file listing any orphaned parts. It is
sometimes useful in diagnosing and repairing corrupted or
damaged NDB tables containing
BLOB or
TEXT columns.

Unless you use the --help
option, you must specify an action to be performed by including
one or more of the options
--check-orphans,
--delete-orphans, or
--dump-file. These options
cause ndb_blob_tool to check for orphaned
BLOB parts, remove any orphaned BLOB parts, and generate a dump
file listing orphaned BLOB parts, respectively, and are
described in more detail later in this section.

You must also specify the name of a table when invoking
ndb_blob_tool. In addition, you can
optionally follow the table name with the (comma-separated)
names of one or more BLOB or
TEXT columns from that table. If
no columns are listed, the tool works on all of the table's
BLOB and
TEXT columns. If you need to
specify a database, use the
--database
(-d) option.

The --verbose option
provides additional information in the output about the
tool's progress.

The tool reports that there are no NDB BLOB
column parts associated with column c1, even
though c1 is a
TEXT column. This is due to the
fact that, in an NDB table, only
the first 256 bytes of a BLOB or
TEXT column value are stored
inline, and only the excess, if any, is stored separately; thus,
if there are no values using more than 256 bytes in a given
column of one of these types, no BLOB column
parts are created by NDB for this column. See
Section 11.7, “Data Type Storage Requirements”, for more information.